| 简介 |
PURPOSE : To obtain a magnetic card for which information erasure and writing intended for forgery are infeasible. CONSTITUTION : The magnetic card 1 obtd. by forming a magnetic layer 3 consisting of magnetic powder magnetized to at least 25% of saturation magnetization by an impressed magnetic field of at least half the magnitude of the coercive force on a card substrate 2, is used. Initial information is recorded in an existing information region 51 exclusive of at least one point of information regions 52 of unrecorded parts made to remain in a prescribed direction at the time of magnetic recording on the magnetic layer in the prescribed direction. Further, new information to be recorded afterward is recorded in the information region of the unrecorded part without erasing the existing information. The magnetic powder is preferably formed by mixing powder consisting of an RT5 (where R is at least one kind of rare earth elements (including Y) essentially consisting of Sm, and T is at least one kind of transition metal essentially consisting of Co) intermetallic compd. phase as a main phase and powder consisting of an R2 T7 intermetallic compd. phase as a main phase. |
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